Field of Invention
The present invention relates to the field of polarization optical fiber sensing technology, and more particularly to a polarization scrambler based on Faraday magneto-optic effect.
Description of Related Arts
The polarization scrambler is mainly used for any optical systems which are sensitive to the polarization states and unable to control the polarization states thereof. The purpose of the polarization scrambler is to rapidly change the polarization state of the system, so as to achieve the average polarization of the data, thereby improving the signal to noise ratio of the system. America Agiltron Company (MA, USA) and China Suzhou Bonphot Optoelectronics Co., Ltd. adopt E-O crystal wave plates, whose principle is that apply a high voltage to control the phase shift of the wave plate, and speed can reach the order of ten nanoseconds. America General Photonics Corporation (CA, USA) developed an all-fiber polarization scrambler, which uses single-mode fibers under stress to change the polarization state; the stress is applied to the SM fibers in the form of PZT at a velocity in the order of microseconds. However, the above two kinds of polarization scramblers are expensive. China Beijing Qi-Red Photoelectric Technology Co., Ltd. developed a polarization scrambler which is based on high-speed rotating fiber wave plates. The polarization scrambler has advantages of low cost and compact structure. However, due to mechanical movement, its service life is affected.